1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * net/sched/sch_prio.c Simple 3-band priority "scheduler".
4 *
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 * Fixes: 19990609: J Hadi Salim <hadi@nortelnetworks.com>:
7 * Init -- EINVAL when opt undefined
8 */
9
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/types.h>
13#include <linux/kernel.h>
14#include <linux/string.h>
15#include <linux/errno.h>
16#include <linux/skbuff.h>
17#include <net/netlink.h>
18#include <net/pkt_sched.h>
19#include <net/pkt_cls.h>
20
21struct prio_sched_data {
22 int bands;
23 struct tcf_proto __rcu *filter_list;
24 struct tcf_block *block;
25 u8 prio2band[TC_PRIO_MAX+1];
26 struct Qdisc *queues[TCQ_PRIO_BANDS];
27};
28
29
30static struct Qdisc *
31prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
32{
33 struct prio_sched_data *q = qdisc_priv(sch);
34 u32 band = skb->priority;
35 struct tcf_result res;
36 struct tcf_proto *fl;
37 int err;
38
39 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
40 if (TC_H_MAJ(skb->priority) != sch->handle) {
41 fl = rcu_dereference_bh(q->filter_list);
42 err = tcf_classify(skb, NULL, tp: fl, res: &res, compat_mode: false);
43#ifdef CONFIG_NET_CLS_ACT
44 switch (err) {
45 case TC_ACT_STOLEN:
46 case TC_ACT_QUEUED:
47 case TC_ACT_TRAP:
48 *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
49 fallthrough;
50 case TC_ACT_SHOT:
51 return NULL;
52 }
53#endif
54 if (!fl || err < 0) {
55 if (TC_H_MAJ(band))
56 band = 0;
57 return q->queues[q->prio2band[band & TC_PRIO_MAX]];
58 }
59 band = res.classid;
60 }
61 band = TC_H_MIN(band) - 1;
62 if (band >= q->bands)
63 return q->queues[q->prio2band[0]];
64
65 return q->queues[band];
66}
67
68static int
69prio_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
70{
71 unsigned int len = qdisc_pkt_len(skb);
72 struct Qdisc *qdisc;
73 int ret;
74
75 qdisc = prio_classify(skb, sch, qerr: &ret);
76#ifdef CONFIG_NET_CLS_ACT
77 if (qdisc == NULL) {
78
79 if (ret & __NET_XMIT_BYPASS)
80 qdisc_qstats_drop(sch);
81 __qdisc_drop(skb, to_free);
82 return ret;
83 }
84#endif
85
86 ret = qdisc_enqueue(skb, sch: qdisc, to_free);
87 if (ret == NET_XMIT_SUCCESS) {
88 sch->qstats.backlog += len;
89 sch->q.qlen++;
90 return NET_XMIT_SUCCESS;
91 }
92 if (net_xmit_drop_count(ret))
93 qdisc_qstats_drop(sch);
94 return ret;
95}
96
97static struct sk_buff *prio_peek(struct Qdisc *sch)
98{
99 struct prio_sched_data *q = qdisc_priv(sch);
100 int prio;
101
102 for (prio = 0; prio < q->bands; prio++) {
103 struct Qdisc *qdisc = q->queues[prio];
104 struct sk_buff *skb = qdisc->ops->peek(qdisc);
105 if (skb)
106 return skb;
107 }
108 return NULL;
109}
110
111static struct sk_buff *prio_dequeue(struct Qdisc *sch)
112{
113 struct prio_sched_data *q = qdisc_priv(sch);
114 int prio;
115
116 for (prio = 0; prio < q->bands; prio++) {
117 struct Qdisc *qdisc = q->queues[prio];
118 struct sk_buff *skb = qdisc_dequeue_peeked(sch: qdisc);
119 if (skb) {
120 qdisc_bstats_update(sch, skb);
121 qdisc_qstats_backlog_dec(sch, skb);
122 sch->q.qlen--;
123 return skb;
124 }
125 }
126 return NULL;
127
128}
129
130static void
131prio_reset(struct Qdisc *sch)
132{
133 int prio;
134 struct prio_sched_data *q = qdisc_priv(sch);
135
136 for (prio = 0; prio < q->bands; prio++)
137 qdisc_reset(qdisc: q->queues[prio]);
138}
139
140static int prio_offload(struct Qdisc *sch, struct tc_prio_qopt *qopt)
141{
142 struct net_device *dev = qdisc_dev(qdisc: sch);
143 struct tc_prio_qopt_offload opt = {
144 .handle = sch->handle,
145 .parent = sch->parent,
146 };
147
148 if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
149 return -EOPNOTSUPP;
150
151 if (qopt) {
152 opt.command = TC_PRIO_REPLACE;
153 opt.replace_params.bands = qopt->bands;
154 memcpy(&opt.replace_params.priomap, qopt->priomap,
155 TC_PRIO_MAX + 1);
156 opt.replace_params.qstats = &sch->qstats;
157 } else {
158 opt.command = TC_PRIO_DESTROY;
159 }
160
161 return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_PRIO, &opt);
162}
163
164static void
165prio_destroy(struct Qdisc *sch)
166{
167 int prio;
168 struct prio_sched_data *q = qdisc_priv(sch);
169
170 tcf_block_put(block: q->block);
171 prio_offload(sch, NULL);
172 for (prio = 0; prio < q->bands; prio++)
173 qdisc_put(qdisc: q->queues[prio]);
174}
175
176static int prio_tune(struct Qdisc *sch, struct nlattr *opt,
177 struct netlink_ext_ack *extack)
178{
179 struct prio_sched_data *q = qdisc_priv(sch);
180 struct Qdisc *queues[TCQ_PRIO_BANDS];
181 int oldbands = q->bands, i;
182 struct tc_prio_qopt *qopt;
183
184 if (nla_len(nla: opt) < sizeof(*qopt))
185 return -EINVAL;
186 qopt = nla_data(nla: opt);
187
188 if (qopt->bands > TCQ_PRIO_BANDS || qopt->bands < TCQ_MIN_PRIO_BANDS)
189 return -EINVAL;
190
191 for (i = 0; i <= TC_PRIO_MAX; i++) {
192 if (qopt->priomap[i] >= qopt->bands)
193 return -EINVAL;
194 }
195
196 /* Before commit, make sure we can allocate all new qdiscs */
197 for (i = oldbands; i < qopt->bands; i++) {
198 queues[i] = qdisc_create_dflt(dev_queue: sch->dev_queue, ops: &pfifo_qdisc_ops,
199 TC_H_MAKE(sch->handle, i + 1),
200 extack);
201 if (!queues[i]) {
202 while (i > oldbands)
203 qdisc_put(qdisc: queues[--i]);
204 return -ENOMEM;
205 }
206 }
207
208 prio_offload(sch, qopt);
209 sch_tree_lock(q: sch);
210 q->bands = qopt->bands;
211 memcpy(q->prio2band, qopt->priomap, TC_PRIO_MAX+1);
212
213 for (i = q->bands; i < oldbands; i++)
214 qdisc_tree_flush_backlog(sch: q->queues[i]);
215
216 for (i = oldbands; i < q->bands; i++) {
217 q->queues[i] = queues[i];
218 if (q->queues[i] != &noop_qdisc)
219 qdisc_hash_add(q: q->queues[i], invisible: true);
220 }
221
222 sch_tree_unlock(q: sch);
223
224 for (i = q->bands; i < oldbands; i++)
225 qdisc_put(qdisc: q->queues[i]);
226 return 0;
227}
228
229static int prio_init(struct Qdisc *sch, struct nlattr *opt,
230 struct netlink_ext_ack *extack)
231{
232 struct prio_sched_data *q = qdisc_priv(sch);
233 int err;
234
235 if (!opt)
236 return -EINVAL;
237
238 err = tcf_block_get(p_block: &q->block, p_filter_chain: &q->filter_list, q: sch, extack);
239 if (err)
240 return err;
241
242 return prio_tune(sch, opt, extack);
243}
244
245static int prio_dump_offload(struct Qdisc *sch)
246{
247 struct tc_prio_qopt_offload hw_stats = {
248 .command = TC_PRIO_STATS,
249 .handle = sch->handle,
250 .parent = sch->parent,
251 {
252 .stats = {
253 .bstats = &sch->bstats,
254 .qstats = &sch->qstats,
255 },
256 },
257 };
258
259 return qdisc_offload_dump_helper(q: sch, type: TC_SETUP_QDISC_PRIO, type_data: &hw_stats);
260}
261
262static int prio_dump(struct Qdisc *sch, struct sk_buff *skb)
263{
264 struct prio_sched_data *q = qdisc_priv(sch);
265 unsigned char *b = skb_tail_pointer(skb);
266 struct tc_prio_qopt opt;
267 int err;
268
269 opt.bands = q->bands;
270 memcpy(&opt.priomap, q->prio2band, TC_PRIO_MAX + 1);
271
272 err = prio_dump_offload(sch);
273 if (err)
274 goto nla_put_failure;
275
276 if (nla_put(skb, attrtype: TCA_OPTIONS, attrlen: sizeof(opt), data: &opt))
277 goto nla_put_failure;
278
279 return skb->len;
280
281nla_put_failure:
282 nlmsg_trim(skb, mark: b);
283 return -1;
284}
285
286static int prio_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new,
287 struct Qdisc **old, struct netlink_ext_ack *extack)
288{
289 struct prio_sched_data *q = qdisc_priv(sch);
290 struct tc_prio_qopt_offload graft_offload;
291 unsigned long band = arg - 1;
292
293 if (!new) {
294 new = qdisc_create_dflt(dev_queue: sch->dev_queue, ops: &pfifo_qdisc_ops,
295 TC_H_MAKE(sch->handle, arg), extack);
296 if (!new)
297 new = &noop_qdisc;
298 else
299 qdisc_hash_add(q: new, invisible: true);
300 }
301
302 *old = qdisc_replace(sch, new, pold: &q->queues[band]);
303
304 graft_offload.handle = sch->handle;
305 graft_offload.parent = sch->parent;
306 graft_offload.graft_params.band = band;
307 graft_offload.graft_params.child_handle = new->handle;
308 graft_offload.command = TC_PRIO_GRAFT;
309
310 qdisc_offload_graft_helper(dev: qdisc_dev(qdisc: sch), sch, new, old: *old,
311 type: TC_SETUP_QDISC_PRIO, type_data: &graft_offload,
312 extack);
313 return 0;
314}
315
316static struct Qdisc *
317prio_leaf(struct Qdisc *sch, unsigned long arg)
318{
319 struct prio_sched_data *q = qdisc_priv(sch);
320 unsigned long band = arg - 1;
321
322 return q->queues[band];
323}
324
325static unsigned long prio_find(struct Qdisc *sch, u32 classid)
326{
327 struct prio_sched_data *q = qdisc_priv(sch);
328 unsigned long band = TC_H_MIN(classid);
329
330 if (band - 1 >= q->bands)
331 return 0;
332 return band;
333}
334
335static unsigned long prio_bind(struct Qdisc *sch, unsigned long parent, u32 classid)
336{
337 return prio_find(sch, classid);
338}
339
340
341static void prio_unbind(struct Qdisc *q, unsigned long cl)
342{
343}
344
345static int prio_dump_class(struct Qdisc *sch, unsigned long cl, struct sk_buff *skb,
346 struct tcmsg *tcm)
347{
348 struct prio_sched_data *q = qdisc_priv(sch);
349
350 tcm->tcm_handle |= TC_H_MIN(cl);
351 tcm->tcm_info = q->queues[cl-1]->handle;
352 return 0;
353}
354
355static int prio_dump_class_stats(struct Qdisc *sch, unsigned long cl,
356 struct gnet_dump *d)
357{
358 struct prio_sched_data *q = qdisc_priv(sch);
359 struct Qdisc *cl_q;
360
361 cl_q = q->queues[cl - 1];
362 if (gnet_stats_copy_basic(d, cpu: cl_q->cpu_bstats,
363 b: &cl_q->bstats, running: true) < 0 ||
364 qdisc_qstats_copy(d, sch: cl_q) < 0)
365 return -1;
366
367 return 0;
368}
369
370static void prio_walk(struct Qdisc *sch, struct qdisc_walker *arg)
371{
372 struct prio_sched_data *q = qdisc_priv(sch);
373 int prio;
374
375 if (arg->stop)
376 return;
377
378 for (prio = 0; prio < q->bands; prio++) {
379 if (!tc_qdisc_stats_dump(sch, cl: prio + 1, arg))
380 break;
381 }
382}
383
384static struct tcf_block *prio_tcf_block(struct Qdisc *sch, unsigned long cl,
385 struct netlink_ext_ack *extack)
386{
387 struct prio_sched_data *q = qdisc_priv(sch);
388
389 if (cl)
390 return NULL;
391 return q->block;
392}
393
394static const struct Qdisc_class_ops prio_class_ops = {
395 .graft = prio_graft,
396 .leaf = prio_leaf,
397 .find = prio_find,
398 .walk = prio_walk,
399 .tcf_block = prio_tcf_block,
400 .bind_tcf = prio_bind,
401 .unbind_tcf = prio_unbind,
402 .dump = prio_dump_class,
403 .dump_stats = prio_dump_class_stats,
404};
405
406static struct Qdisc_ops prio_qdisc_ops __read_mostly = {
407 .next = NULL,
408 .cl_ops = &prio_class_ops,
409 .id = "prio",
410 .priv_size = sizeof(struct prio_sched_data),
411 .enqueue = prio_enqueue,
412 .dequeue = prio_dequeue,
413 .peek = prio_peek,
414 .init = prio_init,
415 .reset = prio_reset,
416 .destroy = prio_destroy,
417 .change = prio_tune,
418 .dump = prio_dump,
419 .owner = THIS_MODULE,
420};
421
422static int __init prio_module_init(void)
423{
424 return register_qdisc(qops: &prio_qdisc_ops);
425}
426
427static void __exit prio_module_exit(void)
428{
429 unregister_qdisc(qops: &prio_qdisc_ops);
430}
431
432module_init(prio_module_init)
433module_exit(prio_module_exit)
434
435MODULE_LICENSE("GPL");
436

source code of linux/net/sched/sch_prio.c